1. Get a round box. Mark in pencil where the lids comes down to.
2. Make up some plaster of paris according to the directions. Mix in a half cup of powdered poster paint. Add a little more water until the plaster is smooth and of desired consistency.
3. Grab a knife and smooth the plaster onto the sides and top of the box, justl ike you're icing a cake. Make sure you don't go above the pencil line you drew earlier or you won't be able to put the lid back on. While the plaster is still wet push in some candle holders.
4. Put the lid on and you have a finished cake. You could smooth out the plaster more but my actual cakes usually look more like this so I figured we'd go with the whole "homemade" look.
5. Put the correct number of candles in and light them. Sing Happy Birthday then blow them out.
6. Open up and take out your card and present.